Transcript Methods of studying the brain

Methods of studying the
brain: A brief history
First… a few more basic facts about your brain!
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Approximately 3 lbs.; slightly larger than size of
an adult fist
2% of total body weight; burns 70% of your
body’s glucose
100 billion+ neurons; trillions of synapses
Biochemical signals travel at 220 mph
Half of the 30,000 genes are dedicated to the
nervous system
The brain itself feels no pain, but registers it from
everywhere else
Early 1800s
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Phrenology: measuring
the bumps on peoples’
heads
They were wrong about
bumps; right about the
brain having localized
functions!
http://www.bc.edu/bc_org
/avp/cas/fnart/phrenology/
phrenology_frames.html
1848: Phineas Gage
http://youtu.be/9QXI_BxlY7M
1930s: Prefrontal lobotomies
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Dr. Walter Freeman: surgical disconnection of
the frontal lobes from the thalamus with an
icepick
Eliminated severe behavioral problems; also
took away emotions, problem solving, thinking
By 1949, 5,000 done annually
http://www.pbs.org/wgbh/americanexperience/films/lobot
omist/
http://youtu.be/_0aNILW6ILk
1950s: Electrical Stimulation of the Brain
1954: James Olds and Peter Milner placed an electrode in
the hypothalamus of the brains of rats by mistake and
discovered the pleasure center of the brain
 When the rats learned that they could control the
electrical stimulation by pressing a lever, they pressed it
7,000 times an hour (endorphins).
 http://accidentalmind.org/the_discovery_of_brain_plea.ht
ml
 1969: Jose Delgado’s “matador” experiment:
stimoceiver
 http://wireheading.com/matador.html
Selective lesioning
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Selectively damaging
parts of the brain using
electrical instrument
Only used in animals…
obviously.
Rat hypothalamus study
Accidents and brain
damage are often studied
in human beings.
And now…
For modern technology!
Electroencephalogram (EEG)
Computerized Axial
Tomography (CAT)
Positron Emission
Tomography (PET)
Magnetic Resonance Imaging
(MRI)
fMRI Scans
What love looks like in an
fMRI Scan!